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-   -   Car feels loose (https://www.ft86club.com/forums/showthread.php?t=124894)

Riftur 01-24-2018 07:33 AM

Car feels loose
 
For some reason my cars rear end feels loose when cornering. There is no damage that is causing this (had the car put on a lift and was told everything looks fine. The only thing I can think of is the psi in my tires along with the colder air we have been experiencing but I am in Florida and the coldest its been was only in the 40's. I have low profile tires with a max psi of 51 and I am currently at 44.3. Any idea what I should have the PSI at for the tires to stick a bit better? This only started a month ago and my tires only have like 8k miles on them.

dowroa 01-24-2018 07:48 AM

Which "low profile" tires?

Why are you at 44.3 psi? Hot or cold?

Stock suspension? Stock camber? Have you played with anything?

Lower pressure in rear at DD pressures generally == more stick.

If your tires have hardened, it can cause them to drive worse.

Personally, I would start with the tires cold, and inflate them only to what is on the side panel of the car.

Still, need a lot more information before an known correction can be given.

Tcoat 01-24-2018 07:58 AM

Temperatures in the 40s have bad effects on summer performance tires. They get pretty hard and slick. There is little point in changing your tires for the short periods you have those low temps so just be aware that the tires will lose traction easily and drive accordingly. Changing the PSI will do you no good at all.
Welcome to my world for at least 5 months of the year! At least you don't have deep snow to contend with.

Riftur 01-24-2018 08:07 AM

Yeah i should have added a bit more info. Running TigerPaw CTZ all season 245/40/zr17. I checked the PSi before driving the car and it was 67 degrees outside and tires were cold. The tires are only about 7-8 months old. Everything on the car is stock except the rim which are rays gramlights 57xtreme 17 inch

Riftur 01-24-2018 08:09 AM

Quote:

Originally Posted by Tcoat (Post 3032777)
Temperatures in the 40s have bad effects on summer performance tires. They get pretty hard and slick. There is little point in changing your tires for the short periods you have those low temps so just be aware that the tires will lose traction easily and drive accordingly. Changing the PSI will do you no good at all.
Welcome to my world for at least 5 months of the year! At least you don't have deep snow to contend with.

So should i put it back to 51 or closer to it?

Riftur 01-24-2018 08:13 AM

Forgot to reply to this message 'Yeah i should have added a bit more info. Running TigerPaw CTZ all season 245/40/zr17. I checked the PSi before driving the car and it was 67 degrees outside and tires were cold. The tires are only about 7-8 months old. Everything on the car is stock except the rim which are rays gramlights 57xtreme 17 inch,

Tcoat 01-24-2018 08:22 AM

Quote:

Originally Posted by Riftur (Post 3032779)
So should i put it back to 51 or closer to it?

It won't make much difference but I would run a slightly lower pressure than that if I was in your position. The higher pressure makes your already cold hardened tires even harder. The 51 on the tire is the max it should be run at not the recommended pressure. The recommended pressure for these cars is 35 so I think that I would run them someplace around 38 to 40 in the cold. The 51 is extremely high even when hot. I have never run any type/make/model of tire over 40 on any car.
Even the "all season" tires you are running feel the impact of the cold. The situation would be much worse if you were running a summer only tire.

Riftur 01-24-2018 08:31 AM

Quote:

Originally Posted by Tcoat (Post 3032781)
It won't make much difference but I would run a slightly lower pressure than that if I was in your position. The higher pressure makes your already cold hardened tires even harder. The 51 on the tire is the max it should be run at not the recommended pressure. The recommended pressure for these cars is 35 so I think that I would run them someplace around 38 to 40 in the cold. The 51 is extremely high even when hot. I have never run any type/make/model of tire over 40 on any car.
Even the "all season" tires you are running feel the impact of the cold. The situation would be much worse if you were running a summer only tire.

These are the first tires I ever bought with such a high max PSI. I never had any of my tires over 35 before these. I will lower it back down to 38 and see if that makes a difference. Thanks for the suggestions.

ZDan 01-24-2018 09:08 AM

Short answer: 35psi

44psi is ridiculously high already, 51psi is absurd!
You do NOT go by the max cold pressure on the tire sidewall! You would only run that much pressure if you needed to support the maximum weight the tire is rated for, which you do not.

Somewhere on the car there's a placard that gives appropriate tire pressures (driver's side door or door jamb probably?), which is 35psi.

ermax 01-24-2018 09:18 AM

Max PSI is just that... Max. That is't where you need to run them though. The suggested PSI is based on the tire dimensions and weight of the car. Put them to the recommended PSI which is on the door jam.

44psi cold even in just 60F is too high. Worse would be if only your rears are set that high.

More Pressure does not equal More Grip

Lets say you have the fronts at 35 and the rears at 44. You are going to have some fairly significant oversteer.

StraightOuttaCanadaEh 01-24-2018 09:54 AM

Wow 51 lol. I was on 35 for a while, decided it was too hard and now I'm at 32. Absolutely it's the tire pressure. I remember on my mountain bikes I'd take the road at 30-35 psi and on the trails I was at about 19-20. A difference of even 1-2 psi was noticeable.

Twinz 01-24-2018 09:56 AM

Quote:

Originally Posted by dowroa (Post 3032775)

Personally, I would start with the tires cold, and inflate them only to what is on the side panel of the car.

This.

Riftur 01-24-2018 10:06 AM

Everyone keeps stating that I do not understand what max PSI stands for. Please stop with this.

Spuds 01-24-2018 10:45 AM

Quote:

Originally Posted by Riftur (Post 3032810)
Everyone keeps stating that I do not understand what max PSI stands for. Please stop with this.

Why were you running 43 psi when the recommended pressures for the car are 35? I think everyone is just confused as to that part since it's not making logical sense, unless you have very strange tires?

On stock tires, 35 psi cold increases to 38psi hot with normal street driving by my observation. Ideally a different tire of the same size would be at 38 hot as well (again, street use only, and doesn't account for differences in structure). However, you actually have a wider tire than stock, so I would think it would be better to run a slightly lower hot tire pressure to maintain the appropriate contact patch.

Something else to keep in mind, lower pressures heat the rubber up more. Hotter rubber usually means more grip and more wear.


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